The background description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.
Ionized physical vapor deposition (iPVD) processes typically involve multiple, discrete processing steps. Some of the processing steps may involve the use of plasma that is operated with a different RF power and/or a different etch/deposition (E/D) ratio. Currently, the DC plasma is extinguished between each of the steps of an integration stack and re-ignited for a subsequent step.
At the beginning of a processing step, the plasma is struck and becomes stable after a predetermined period. Film that is deposited before the plasma is stable will have low quality, which lowers yield. The amount of time associated with the stabilization of the plasma also lowers substrate throughput.
Some advanced iPVD processes for copper utilize high density plasma to facilitate Cu reflow. Reflow provides high sidewall/bottom Cu coverage and low overhang with minimum or no deposition on the field.